In the movie, Reign Over Me, the main character--Charlie Finman--is suffering from PTSD(Posttraumatic Stress disorder). According to the website, mentalhealth.com, Posttraumatic Stress Disorder "is a condition characterized by intense fear, helplessness, or horror resulting form the exposure to extreme trauma." Charlie was definitely exposed to extreme trauma--a result of the loss of his wife and three children in the 911 terror.

Posttraumatic Stress Disorder is a condition of fear and horror resulting from extreme trauma. The trauma Charlie experienced with the 911 terror must have triggered the disorder. People with this disorder oftentimes feel painfully guilty for surviving when others could not. His life must have stopped when his wife died.

He also has a hard time socializing, and therefor his relationships are unstable. This may be diagnosed as Social Phobia or Social Anxiety Disorder, which causes "abnormally considerable distress and impaired ability to function in at least some areas of daily life". He is also potentially Generalized Disorder, which is the fear of being judged by others. However, I believe Charlie's condition is closer to anxiety and depression. People feel anxious when they are depressed--possibly by losing your family members.

In order to recover from these disorders, Charlie should stop keeping things to himself and open up. When you have PTSD it is very difficult dealing with the past. However, speaking up to a therapist is a good treatment for Charlie. If I were a friend of Charlie, I would try my best to convince Charlie into visiting a therapist. Within many types of therapist treatment, Cognitive-behavioral therapy (CBT) is most likely to help Charlie the most. CBT is proven to be the most effective for people suffering with PTSD. Selective serotonin reuptake inhibitor (SSRI) is a type of drug that may help treat Posttraumatic Stress Disorder. These drugs are also used in depression. Depression may be the potential cause for PTSD, and vice versa. As Charlie's friend, I would suggest Charlie to try and avoid depression. Depression leads to many other disorders, some even worse than PTSDs.

http://www.mentalhealth.com
http://ptsd.about.com/od/relatedconditions/a/depressionPTSD.htm